The present invention relates to rotating phased-array antennas, and more particularly to a method and apparatus for compensating for the effects of the antenna's rotation.
In radar systems with rotating phased-array antennas, there are two basic effects of the rotations which reduce an adaptive radar processor's sensitivity and its ability to suppress interference. The first effect is that all radiation sources appear to be extended because successive time samples from the same source originate at different angles relative to the antenna normal. The second effect is that the rotation imparts a doppler spread to radar returns since samples received at one edge of the rotating antenna exhibit a positive doppler shift, and samples received at the opposite edge experience a negative doppler shift, intermediate samples being uniformly spread in between these extremes. Neither effect should be neglected in an adaptive radar processing system, and failure to compensate for the effects leads to significant degradation to the performance of an adaptive processor in the presence of interference.
It would therefore represent an advance in the art to provide a means to compensate for the effects of the rotation on a rotating phased-array antenna.